Pontchartrain Runneth Over

With 145 miles-per-hour hurricane winds rushing in from the east on the morning of August 29, New Orleans saw more than a sunrise. The wrath of Katrina’s catastrophic category 5 winds was more than the original design of the New Orleans levee system, residents and the government could handle.[no]
Designed to buffer against a fast-moving category 3 hurricane, the levees could not withstand the winds that attacked the Gulf Coast. While the cause of Katrina and the toll it has taken is analyzed and debated, MSU professors and officials delve into the underlying problems Katrina has brought to the surface.
Three hours after initial landfall, Katrina’s winds ebbed to a category 3, but 6-8 feet of water from storm surges began to blanket areas of New Orleans. Eventually, three levee walls failed, leaving many rooftops submerged in the city, whose elevation is nine feet below sea level.
Civil and environmental engineering professor, Milind V. Khire, suggested three possibilities for the levee failures. According to Khire, the impact force of the storm surge may have toppled the embedded concrete I-walls which play a critical role in the earthen structure of the levees. Another suggestion was water seepage might have scoured the down gradient of the levee, resulting in saturation and the collapse of the structure. Khire also suggested while excessive seepage of water could lead to piping at the down gradient ground surface, washing of the levee could have been a result.
The latest catastrophe hits home to Robert Bea, a civil and environmental engineering professor at the University of California Berkley and a former New Orleans resident and hurricane victim. In 1965, Hurricane Betsy, a category 4, destroyed his home and possessions.
“This is an opportunity to make America proud of how it can rebuild in the wake of Hurricane Katrina,” said Bea. “A concert of approaches should be used that will match the natural and social infrastructure.”
“We don’t know yet if the levees performed well until they were overtopped, and then failed, or if they failed before that,” said Engineering Associate Dean Thomas F. Wolff, who is also a member of the American Society of Civil Engineers’ levee assessment team. Wolff will be one of about 15 engineers in the country examining the levee failures in upcoming weeks. “The committee I am on will look into those questions,” he said.
While countries such as Japan and the Netherlands spend millions of dollars on levee building and maintenance to protect their citizens from Mother Nature’s unpredictability, focus on water projects in the United States is proposed, but not highly funded.
“In 2004, the Army Corps of Engineers asked Congress for $500 million to renovate the New Orleans levee system,” American economic history professor, Dr. James Anderson, said. “Unfortunately, President Bush cut funding by 80 percent, roughly leaving only $160 million.”
“Levee maintenance is the national government’s responsibility,” Anderson said. “I believe this is the single greatest failure of national government in response to a national disaster in American history.”
While recommended solutions include providing higher levels of safety to the New Orleans infrastructure by improving hurricane surge development into Lake Pontchartrain and broadening the Mississippi River floodplain and attributed wetlands to provide another means of surge water dissipation, Khire suggests a more technological manipulation of the flood plain terrain. “A multi-cell protection design in combination with super levees would provide New Orleans with defenses against an entire devastation,” said Khire.
The multi-cell design would provide each segment of the city with protection from its neighbor in case of flooding from hurricane surges or intense tropical storms. Super levees, unlike the conventional levees seen in New Orleans, feature wide bases and a gradually steeper slope.
The biggest difference lies in ground elevation on the protected side of the levee. The levees in New Orleans had ground level near the same elevation on both sides. Super levees feature ground nearing the top of the levee, but the ground slopes gradually into a river or exiting system in the distance. This reduces what we currently see in New Orleans – standing water.
“Experience and technology can provide the ways to adequately protect the city of New Orleans,” said Bea. “The major technology is to properly mobilize the will of the American public and government to provide the long-term resources required for rebuilding.”